Pawl-and-ratchet mechanism.



H. M. RAMSAY & J. A. fllCKABAU GH PAWL AND RATCHET MECHANISM.

APPLICATION FILED JULY 5.1916.

Patented Dec. 5, 1916.

' WITNESS:

30.which the pawl rests with 45 is employed 55 threaded onto the end of HENRY M. RAMSAY, OF ALTOONA, AND JU'S'IUS A. RICKABAUGH, F PITTSBURGH,

" PEN N SYLVA NIA.

eonora.

Specification of Letters Patent.

Application filed July 5, 1916. Serial No. 107,495.

To all whom it may concern Be it known that we, HENRY M. Ramsay and J USTUS A. RICKABAUGH, both citizens of the United States, residing, respectively,

at Altoona, in the countyof Blair and State of Pennsylvania, and Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improven'lents in Pawl-and-Ratchet Mechanism, of which the following is a specification.

The invention relates to pawl and ratchet mechanism, and more particularly to the pawl construction which is shown as applied to use in connection with a hand brake on a car. The invention has for-its principal objects: the provision of an improved self acting pawl, simple in construction and pos-- itive in action; and the provision-of a pawl in which no. additional parts are required by the self acting feature, which is substantially as cheap as the ordinary non-automatic pawl and which will wear indefinitely without getting out of order. One, embodi- 25.1nent of the invention is illustrated in the accompanying drawings, wherein I Figure l is a plan view of the mechanism; Fig. 2 is a side elevation; Fig. 3 is a plan view of the portion of the device upon the pawl removed; and F ig. at is a section through the pawl taken alone on the line IV-IV of Fig. 1.

The ratchet wheel 1 and the pawl 52 are preferablycarried on a single metal base plate 3 which plate is held in position on the ear member or other support 4 (Fig. 2) by means of the bolts 5 and 6.

The ratchet wheel 1 is mounted for rotation on the upstanding lug 7 of the base plate and may be of any approved form, the invention residingparticularly in the pawl regardless of the kind of ratchet wheel with which it is used. The usual guard 8 also integral with the base plate 3, and the ratchet wheel is rotated by the shaft 9 secured in the hub of the ratchet wheel in any desired wav.

The left hand end of the base plate is provided with an integral upstandingsleeve 10 upon which the pawl 2 is pivoted, and resting upon the upper end of this sleeve is the washer 11 held in position against the end of the sleeve by means of the nut 12 the bolt (3. As

indicated in Fig. 2, the washer 11 is spaced above the top of the pawl so that the pawl may slide upward for the purpose hereinafter set forth, and as required by the method ofoperation.

Surrounding the sleeve 10 and projecting upward from the base plate 3 are a pair of cam surfaces marked 13 and let on Fig. 3, the arrows on Fig. 3 indicating the direction in which the surfaces incline upward. The upper ends of these inclined surfaces terminate in flat surfaces 15 and 16 which rest against the under side of the pawl. The character of these surfaces will be understood by reference to Fig. 2, in which the surfaces It and 15 are shown in side elevation. The under surface of the pawl 2 is provided with av pair of downwardly pr jecting lugs 17 (Fig. 2) having their lower edges inclined so as to fit the inclined surfaces 13 and 14:. From the foregoing it will be seen that as the pawl is rotated in a counter-clockwise direction (Fig. 1) to release it from the ratchet teeth. it will be cammed vertically until its upper. face engages the washer 11. If now the pawl is released, it will re- .latented Dec. 5, 1916.

turn to its original position, as indicated- 17 sliding downward and in a clockwise direction upon the inclined cam and 1-1, such movement being due to gravity. As a pawl of thistype is relatively heavy, and. the inclination of the cam surfaces is quite steep, a positive movement of the pawl to operative position is secured, so that the operator is relieved of the necessity of holding the pawl in operative position while he is turning the brake shaft 9 and applying the brake.

It will be seen that the construction herein set forth relatively cheap and simple and that aside from the cam members which are made integral with the base plate, no addition or separate parts are required to make the device automatic as comparedhvith the non-automatic pawl commonly employed in connection with brakes. The pawl itself supplies the necessary operating Weight, so that no additional weight is required, and the mechanism requires no more attention or repair than the ordinary non-automatic pawl. The construction is applicable to the standard type of ratchet wheel now in use and comparatively slight changes only are surfaces 13 required in the pawl and base plate as'compared with standard constructions, so that the device can, be readily substituted for the non-automatic constructions now.in use. Other advantages incident to the cheapness and simplicity of the device will be readily apparent to those skilled in the art.

It will be understood that our invention contemplates modifications and changes as well as a mere reversal of parts 'a pawl-is causedto move rotarily to operating position by weight applied to an inclined surface or some other member is so operated. Whatg we claim is: r 1

1. The combination with substantially horizontal ratchet wheel, of a pawl working around a substantially vertical axis and having a limitedamount of play in a vertical direction, a support for the pawl, and

support arranged to cam the pawl in a vertical direction when it is rotated to disengaged position, and to cause the pawl to rotate automatically in the reverse direction when it is released from such position.

,3. The combination with a ratchet wheel,

of a pawl mounted for rotation abdut an upright axis and for movement longitudt.

Copies of this patent may be obtained forflve cents and that the principle involved is the same whether mounted for rotation about face,

surface opposing pawl, the parts being so arranged that when the pawl is in inoperative position pressure 7 nally" of such axis, pawl turns, and coacting surfaces on the underside of the pawl and the said support and having such a relative inclination that direction, when it is position. a

- 4. In combination, a ratchet wheel member and a pawl member, one of which works about a substantially vertical axis and has rfotated to disengaged a support'on whichthej v '45 the pawl is caused to move in a vertical 7 a limited amount of movementin a vertical direction, and coacting cam surfaces on the underside of such last member and the support on which it turns, arranged so that the weight of such last member causes it to rotate about its axis and give engagement between the two members.-

5; In combination, an operating member an upright axis and having an end which swings toward and from operating position, a support on which the member turns, and coacting inclined surfaces on the underside of the mem'- ber and on said-support arranged to cam the member in a vertical direction when it is rotated to inoperative position, andto cause the member to rotate automatically in the reverse direction when released;

.6. The combination with a ratchet wheel,

of a pawl mounted for rotation about avertical axis and having an upper and a lower the pawl, and another part having a cam the cam surface ofthe is exerted between the cam surfaces tending to rotate the pawl to operative position.

HENRY M. RAMSAY. Y J USTUS A. RICKABAUGl-I.

each, by addressing the "Gomml'ssi oner or -1?atenta,

I Washington, D. O.

a camsurface on one of said faces of 

